1.\" $OpenBSD: hardclock.9,v 1.13 2020/06/26 18:48:31 cheloha Exp $ 2.\" 3.\" Copyright (c) 2001 Kenneth R Westerback 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer, 11.\" without modification, immediately at the beginning of the file. 12.\" 2. The name of the author may not be used to endorse or promote products 13.\" derived from this software without specific prior written permission. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT, 19.\" INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 20.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21.\" SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 23.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 24.\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF 25.\" THE POSSIBILITY OF SUCH DAMAGE. 26.\" 27.Dd $Mdocdate: June 26 2020 $ 28.Dt HARDCLOCK 9 29.Os 30.Sh NAME 31.Nm hardclock 32.Nd real-time system clock 33.Sh SYNOPSIS 34.In sys/systm.h 35.Ft void 36.Fo hardclock 37.Fa "struct clockframe *frame" 38.Fc 39.Sh DESCRIPTION 40.Fn hardclock 41implements the real-time system clock, interrupting 42.Xr hz 9 43times a second. 44The argument 45.Fa frame 46is an opaque, machine dependent structure that encapsulates the 47previous machine state. 48.Pp 49.Fn hardclock 50performs a variety of time related housekeeping tasks, such as: 51.Bl -bullet -offset indent 52.It 53If the current process has virtual or profiling interval 54timers, update the timers and deliver appropriate signals. 55.It 56If there is no separate statistics clock, execute 57.Fn statclock . 58.It 59Increment the time of day, implementing any adjustments requested by 60.Xr adjtime 2 61or required as a result of running an NTP daemon or other configured 62external clock. 63.It 64Update the real-time timeout queue, calling 65.Fn softclock 66directly if the current interrupt priority is low enough. 67.El 68.Sh CODE REFERENCES 69.Fn hardclock 70is implemented in the file 71.Pa sys/kern/kern_clock.c . 72.Sh SEE ALSO 73.Xr adjtime 2 , 74.Xr hz 9 , 75.Xr microtime 9 , 76.Xr spl 9 , 77.Xr timeout 9 78